As midnight tolled and Japan moved into the small hours of Friday morning, Issei Izawa had no idea that anything was amiss in the seething crowd of football fans around him in the heart of Tokyo’s Shibuya entertainment district. Fans in the shirts and face paint of the Samurai Blue were cheering their team on as Japan played Poland in the final group match of the Russia World Cup. And even though Japan were losing, the atmosphere was festive and amicable, 19-year-old Izawa told the South China Morning Post . Among the crowd, however, Japan’s notorious “chikan” – or gropers – were going about their unsavoury hobby. “I heard shouts and screaming at different times, but that is not a surprise given the number of people that were on the streets watching the game and just partying,” he said. “But I’ve seen the social media reports this morning about women being groped in the crowd. “I never saw anything like that or noticed anyone who was in trouble – but it would have been impossible to see because there were just so many people everywhere.” Japan train commuters buy ‘groper insurance’ to defend against sexual assault claims Twitter and other social media were alive with comments by female fans whose evening watching football had been ruined by the attentions of the chikan taking advantage of the crush. “Women should be careful,” one poster said on Twitter. “Someone touched my breasts and my bra hook was nearly undone. I suggest any women be with a man to protect them.” Another female fan added, “I was not wearing a miniskirt but someone was messing with my skirt. I’m glad the Japanese team is winning but I can’t enjoy it because I’m so tense. Today, I dislike football fans.” Japan may bar Julien Blanc, who teaches how to aggressively pick up women There are no reports of police making any arrests in Shibuya connected to people being indecently touched and it seems likely that gropers will take advantage of Japan entering the knockout stage of the tournament to target women once more. The team is expected to play Belgium in the next round on Tuesday. Experts believe that gropers – who have been the target of an aggressive crackdown by authorities on Japan’s railway lines – are likely to have been emboldened by the sheer number of people who do not know each other packed together and also fuelled by alcohol. ‘My desire exploded’: Chinese man arrested for touching woman on Tokyo train “Alcohol is used often as an excuse for bad behaviour in Japanese society,” said Makoto Watanabe, a senior lecturer in communications at Hokkaido Bunkyo University. “It is perhaps based in out cultural background, where a Japanese person’s formal and informal lives are very much separated,” he told the Post . “In this society, it is acceptable to be drunk in an informal setting and that can then be used as an excuse for something that was said or done.” Head of Japanese police anti-groping unit arrested for allegedly molesting girl Claiming to be drunk will not protect a person from punishment if they have broken the law, he said, but it is often sufficient to excuse a minor infraction. It does not stop people from trying it as an excuse for more serious issues, however. This week, for example, an officer of the Shizuoka Prefectural Police’s Community Safety Division was arrested for allegedly molesting a teenage boy on a train on his way home from work, the Sankei newspaper reported. Hiroyuki Asakura, 45, claimed he had been drinking with an acquaintance after work and was drunk. In May, Tatsuya Yamaguchi was forced to resign from popular boy band Tokio after admitting he forcibly kissed a secondary school girl after he had invited her back to his flat. A shamefaced Yamaguchi told reporters that he had been drinking before the incident. Tokyo train gropers evade capture, disrupt services with risky railway line escape routes Given the number of comments that have emerged on social media sites after the most recent Japan football match, authorities are likely to be more vigilant for misbehaviour for the next game, although they will again face difficulties in policing large numbers of people in an open and accessible space.